For factory-farmed pigs, avoiding African swine fever may be about as good as the grim news gets
GREENPORT, New York––With all eyes on the progress of vaccination against the global COVID-19 pandemic, which has to date killed nearly 3.5 million people, the U.S. Department of Agriculture Research Service in early May quietly announced a breakthrough in developing a vaccine to stop African swine fever, a disease responsible for the deaths of from 100 to 200 million pigs since 2007.
African swine fever is also responsible for the births of approximately as many pigs as die or are culled to control the disease, as farmers worldwide race to claim any opportunity to fill an open niche in the market supply chain.
Vaccine will prevent pig births as well as culling
The introduction of a successful vaccine against African swine fever therefore has the potential to spare several hundred million pigs per year from the disease itself and/or culling, and to prevent several hundred million more pigs from being born each year into lives of suffering on factory farms, transportation, and slaughter.
Estimates of the African swine fever toll vary so widely because of conflicting reports about the extent of outbreaks and culling in China, which has about half of all the pigs in the world, and because many other nations known to have had outbreaks have not shared data pertaining to those outbreaks with the international zoonotic disease control community.
The known African swine fever toll in China, between the disease itself and prophylactic culling undertaken to try to keep the disease from spreading, has ranged between 5.6 million and 8.2 million pigs per year.
The African swine fever toll in Vietnam cumulatively exceeds six million, according to government reports.
African swine fever has not yet hit the U.S.
The U.S. has the second largest pig industry, globally, accounting for about 10% of total pig production. African swine fever has not hit the U.S. yet, but fears that it could come to the U.S. next has impelled the USDA Research Service to give development of a preventive vaccine top priority.
Until now there has been no vaccine and no cure for African swine fever, believed to have crossed into domestic pigs from African warthogs and bush pigs.
African swine fever was first identified in Kenya in 1921, but is known to have infected domestic pig herds as early as 1907.
Sporadic outbreaks in Europe, beginning in Lisbon, Portugal, in 1957, were stamped out by culling.
The road leads back to Georgia
A pandemic beginning in the nation of Georgia, however, formerly one of the southernmost states in the Union of Soviet Socialist Republics, has since 2007 evaded control by culling, and has instead swept through most of Europe and Asia, hitting both wild boars and factory-farmed domestic pigs.
The USDA Research Service breakthrough, a Plum Island Animal Disease Center team led by senior scientist Manuel Borca, DVM, announced in the Journal of Virology, is in the words of the industry periodical Pig Progress, that “An African swine fever virus vaccine candidate has been adapted to grow in a cell line, which means that those involved in vaccine production will no longer have to rely on live pigs and their fresh cells for vaccine production.”
Said Borca, through a USDA media release, “This opens the door for large-scale vaccine production, which is a valuable tool for the possible eradication of the virus.”
Oral vaccine possible for wild pigs
Added Pig Progress, “Only last week the news broke that the vaccine was also proven to be working when given oronasally [by mouth and nose] to pigs, which means that there is potential to use it in bait for wild boar populations.“
“The newly developed vaccine,” Pig Progress explained, “grown in a continuous cell line––which means immortalized cells that divide continuously or otherwise indefinitely––has the same characteristics as the original vaccine produced with fresh swine cells.
“The continuous cell line vaccine candidate was tested in a commercial breed of pigs and determined to be safe, protecting pigs against the virus. The research team did not observe any negative effects,” Pig Progress concluded.
New outbreaks in six nations
The Journal of Virology paper appeared almost simultaneously with a May 5, 2021 Yonhap News Agency report from South Korea that African swine fever has reappeared, seven months after it was believed to have been eradicated by a campaign that began by culling 400,000 pigs at 14 farms in 2019.
More than 3,000 wild boars were subsequently killed as suspected African swine flu carriers.
401 pigs were culled at a single farm in Gangwon Province in response to the most recent South Korean African swine fever outbreak.
Earlier 2021 outbreaks occurred in India, Malaysia, the Philippines, and Poland.